Signaling system



Sept. 23, `1952 R. M. MOBERMAN v 2,611,815 l SIGNALING SYSTEM FiledMarch 28, 1950 3 Sliets-Sheet 1 Fnf/250 INVENTOR. RQELoF MAA'RrEN MARIEOBERMAN Sept. 23, 1952 R. M. M. OBERMN 2,611,815

SIGNALING SYSTEM Filed March 28, 195o s shams-sheet z M ev* Polak/25a IF/.vnk Ja'scran INVENTOR. Ruegos MMRTEN MAR/E osERm'Afl BY Sept. 23,1952 R. M. M. OBERMAN 2,611,815

Y SIGNALING SYSTEM I Filed March 28, 195o s sheets-sheet s INVEN TOR.

E "F Mmmm MARIE BY OBERMAN Patented Sept. 23,*.1952

:ASIGNALING SYSTEM 'Roelof M-'M-"Oberman, Thcliafgu Nether'land,lApplcationLMarch 28, 1950, Serial No. V11525451 A ;In `theNetherlands.Julyfll Section'L/libliclfaw 6,90, AllgllStf, `1346 PatentYexpires July 26, '11961 1 'The .present invention:relatestosig-na'lling systems, in particular A for telegraphftransmission, inwhich a number of subscribers may'befc'onnectedto .an exchange r bydouble current orfsingle current lines, A.these `subscribers ibeingVinterconnectediin the -exchange manually orautomatica'lly by .meanssoiarepeaterwhich adapts itselfauto.- maticaliy to the number nature of theincoming 'andxout'goingJ lines'i in :a manner .-not,resulting in signal:distortion iorflimitationfin: speedf-of .operation.

*.'Thisrapplication' isfa nontinuatiomin-partiofmy.copendingaappiicaticnferialNo717139;filed .October 1, 1947.

In knownexchange systemsforgestabiishinginterconnections:betweenitelegraph subscriber4 lines of :differentmatura-t' the subscriber 1 :lines veach terminate.; in @asn-md; repeaterin the; exchange, these repeaters Working on thev sideof'zthe. subscrber`with :current of ,dlierent inaurefgand ion .the sidezof the 1connecting Alin-k :with Acurrent;k of onefand thef :sa-me:11a-ture, e.;gv.f doub1ef.01.11rent,; yso as -.to ofbtairlA a system,: in whichinterconnections ofV arbitrary-subscriber lines may befestab'lished by'one. and the :same connecting1in-11:, Without means. for adapting; thislii'ilmof the natureef the subscriber ;lin es. A

.In -IJ .1 S; Patent 1,959,412 a bidirectional tele-.-graphexchangesystem isrdescribedfin whichzthe lines 'donutterminatein.afixed repeater. @ply ,onerepeater is added inthe ccmloecti-I-lg .-link, serv.- ing tointerconnect-theiines. As theIrepeater does not adapt itself to the nature oitheincoming ,and.outgoing llines, .the application of L-this system is. limited :itc f.exchanges ...interconnecting lines` of identical nature.

It -is ,thef main .obectV of this .inventioncto provide. an.exchangessystem, mvwhichadaptablare.- peaters areadded in the.connecting links .betw ee n lines, lthese repeaters.beingfconnected`-tothe .lines only-when required. .Asthe :subscribers ,do l.nottermi-nateeach in aiixed repeaterconsistng,,of polarized relays, 1- the:number of repeaters :required. may be reduced, whereby anrirnpcntanteconomy-is obtained. Y

Inconsequence :means are r.provided ,inthe connectinglink for.discriminating` @the `nature of :the incomingand outgoinglinmandfcrgadaptingthe circuitofthe repeater .to-.these -1ine s, which.may,besing-lecurrenttwo and iour-Wiredines anddouble currentylines.

f .-.Inmaking..a.connection. to,a singiecur rent l.subscriber yline,-itdst-.necessaryftosadapt thefreg ceiving relay to the line. Thisadaptation is achieyedinzthe systemiaccordineatcithe invention 2k lby-lprolonging al1 the K sing-1e currentHlinesfibehi-ndther'local'f-receiving relay bil-means oflstationaiy individual'compensating r resistances! :which `liae theresistance.:ofthe-subscriber loop.-

#The-repeaters ef the; invention-are so arranged that incoming andoutgoing connections ofidii-` *ferent-,gnature may ibe 'I interconnectedat Willi It will? be' clear romithefdescriptienf that11the=frebeater-lis not only suitablerto-themutualadapt'ationiofsubseriber:lines; belonging tota singlefex', changelbut also sito the*A interconnection ofc-arbitraryfconnectionstoand fromother exchanges.

. A. 'further` object.v oflthe invention. is ltaproyide -localisubscriber arrangements, 1which areisuitable -or hcthosimpiext andfduplexstraic; atgthe-.subf

scriber's: Adesire. sFor... subscribers, i 'usi-nga thea-are rangements-of ;the nventionya possibility exists yto:increaseithe economy.ofeailine usediin mutual traic r by ,simultaneous transmissionsanidrrecep.- tionoverstwo wireepairs;iffnorccpyfoftheir emis .sion isrequired. or,A if .they :fmake usenf amante;- matic transmitter.Subscribersnoterequirngftnis facility are connected1to:the;exchangebicaesingle wirenain 1 v :The ireplacernentf accordingto.the inyentorifo stationarwterminating .apparjatusrcrreachsub: ,scriberconnection asheretofore used; ill-telegram; exchanges by repeaters inthe-connes ng ks on1y:;inerted xrieccssarfn en 51p. the possibi, ot-tesngetbese Lnks Wthcu scrber "The invention will now be describedinra-akelige `exchanges ortootkhelr yps ofse asisrequiredfor;:pieperlyiindeitandiee-thaisalc cuit f lower part of Fig. 1 therepeater is shown having a double current line, which may be theconnection to the exchange of a district subscriber or of anotherexchange. Furthermore an apparatus is shown individual to thesubscribers, and serving to terminate the lines, which apparatusconsists of the line and cut off relays and, for the single currentlines, of the compensating resistance adapting the telegraph relays inthe adaptable repeater to these lines.

Fig. 2 shows the main parts of the connecting link with the adaptablerepeater, in which polarized relays OVR and ZR are the local receivingand transmitting relays, respectively.

In connection with the repeater circuita call iinder OZ. and the rstselecting stage comprislng a group selector GK are shown, while in thelower part of the ligure the register is shown with its connections to aregister nnder RZ, only as far as is required for the explanation of theinyention. The relays EDRi and EDRz discriminate the incoming andoutgoing junctionlines, respectively, in single current and doublecurrent lines and adapt the corresponding parts or the repeater to thekind of current used on these lines.

VOperation of relays DRi and DRz adapts the repeater to duplex-singlecurrent traffic; such operationv may be effected at will by thesubscribers.l The functions of the other relays will be clear from thefollowing description:

. yFigs. 3, 4 and 5 show the different repeater circuits, Which may beestablished by the action of the discriminating relays in the connectinglinks. All unimportant details have been omitted for the sake ofclarity. The parts in the connecting link, more properly belonging tothe repeater are shown, namely the local receiving relay OVR and thevlocal transmitting relay ZR. The make contacts of the discriminatingrelays EDRi, EDRz, DR1 and DRz, forming part of the circuits, are shownin open position, while the cut-oi contacts are shown in closedposition.

In Fig. 3 the repeater is shown in the position required for theinterconnection of two local simplex subscribers. In Fig. 4 the repeateris shown in the position interconnecting two single current duplexsubscribers. vFig 5 shows the circuit of the repeater for theinterconnection of two double current lines, which are terminated byindividual repeaters in the exchange.

yIn Figs. 3 to linclusive the through connections from the callingsubscriber to the register, which are switched oii after the connectionbetween the subscriber is established, are shown in dotted lines.

It will be clear fromthese drawings, that all other -combinations ofincoming and outgoing lines of different kind may also be interconnectedby the adaptable repeater. r v

The adaptation of the repeater, which in normal condition is switchedfor double current lines, to a calling single current subscriber` willnow be described. In normal condition of the subscrlbers set in Fig. 1,a circuit is closed from battery, over the winding of line relay LRi,the back contact of the right-hand change-overseentact of the cut-offrelay CORi, dial contact'NSi, resistance R8, back contact of the upperchangeover ncontact of relay HR, the winding of polar r`elay-lilR, theback contact of the left-hand change-over contact of relay COR; toground. this-condition, owing to the resistance Ra, the current in thecircuit amounts to about 5 mA.-,

the line relay LR; being safely kept at normal by a current of 5 mA.

Furthermore the current direction is such, that the polarized relay ERkeeps its contact opened as shown, so that the printer motor M isstopped. On pressingthe callingkey OT resistance Ra is .bridged by relay",AR. The 'current inthe subscribers loop now increases so much, thatthe operation of the relays LR1 in the exchange and AR in thesubscribers set is accomplished. Relay AR bridges with its front contactthe calling key OT, which thus has only momentarily to be operated.

At the operation of the line relay LRi, in consequence of an incomingcall, the call finders. allotted to the call are started. In Fig. 2 afree call finder OZ with a repeater is shown; the local subscriber isconnected to the rst contacts in the rows of contacts of the callfinder. The righthand front contact of line relay LRi applies negativetest voltage over a resistance R4 to the rst contact of contact row einv all the call finders of this group. Y

At the receipt of a starting mark in one of the line relays, commonstarting relay ASR is operated in a circuit from battery, its ownwinding, the left-hand front contact of relay LRi to ground. v

The iront contact of relay ASR closes in its turn operating circuits forthe starting relays SR1 of all appropriate call iinders. The drivingmagnets of the'call iinders are now energized, the front contacts ofrelaysSRi close'circuts similar to that shown in the drawing frombattery. the winding of driving magnet KM1, a make contact of startingrelay SR1, cut-oiicontacts of test relay CRand oord seizure relay KBR toground. Call finder'O'Z and the other free call finders are permitted tostart.

If call nder OZ of Fig. 2 is the iirst to reach the calling subscriberline, the test relay CR is energized in a circuit from battery,resistance R4, a make contact of relay LRi in Fig. 1, wiper e of callfinder OZ and the high resistance winding of relay CR to ground. At theoperation of relay CR, its make contact applies ground to the lowresistance winding of relay CR, whereby the current increases so much,that the negative test voltage at the contacts in the e-rows of all callfinders becomes insufficient for the operation of other test relays CR.In Vthis manner double tests in this stage of building upv theconnection are prevented. v

In a way analogous to the seizure of a free call finder, a number ofregister 'ilnders are started, one of which connects thecallingvsubscriber to a free register. On the operation of test relay CR groundis applied to a commonregster starting relay RSR, which closes with itsfront contact circuits for the starting relays SR2 of a number ofappropriateuregister finders. Fig. g2 shows a free register iin-der RZ.Relay SR2 applies ground tothe driving magnet KMz of the register nderover the lright hand back contact of relay RBR. the left hand backcontact of relay RCR an-d its own make contact; Ifl the Aregister iinderRZ arrives rst of all at the contacts of the calling connecting link,test voltage is applied to the high resistance Awinding of relay RCR bymeans of the contact in the row a of the register 'rinden On theoperation of relay RCR the register finder stops and the low resistanceWinding-of relay RCR is connected to ground, in order to prevent doubletests.

' As theregistertest relayRCR is energized at the; moment Whenfa;freefregfister-isffound, Qper yating `circuits"are closed for twoholding relays. namely for theregister-holding'relayBBR.; which remainsoperated .during the 'holding 'time of the registe'riin 'a circuit from-=battery,the winding oi relay RBR and a right hand -maket contactoffrelay RCRto. ground, 'and for the cord-holding relay KBR a circuitvfrom #battery` the Winding of relay K-BR, .the b=wiper fofthejregisterfnder RZ, a make'contactof relayR/CR-and the make side'ofthe vchange-over.y contact offrelayfRBR; to vground. Rel-ay KBR. whichhas a r`controllingfunction in theconnecting circuit and .in theregister, .--holds itselil after the connections tothe register lareswitched oi, in a circuit'fover its own fmalcezcontact's and the-'makedotactsFof the/slow'y releasing guarding .relays CRi and (SR2,`theserelfays' being operated in 'aina-nner.. which willfbe describedhereinafter. f

VThe operating of the cord sefzure-relayfKBR hasfsom'e consequences,whichhave' an extraordinarysignicance in the system accordingto theinvention. First'r'elay C'ORilop'erates in a circuit V'from yb'aLttiery, the' winding 'offrelay CORi,.-th'e' c'- Wiperv of thecalli'flnder'OZv and the make jsideof the-'ch'ang'e-ove'r -contact'ofrelayfKBB. to ground, lwhereby' the relays LRi', CR hand RCR are released.'Negative testyo1t-z1.'g"'e'is'noy longer appl-led to .the contactsofthe-aronef callnde'rOZ 'so that effective protectionvTarget-inst'idoli-ble Vtests is infor/ideel.V A A l Furthermore'circuitsIi-frfthe reiaysj, -discri'r'niating theL 'kindoffcalli-iig"line,"areV olos'eiiy a v"nanner"now to be described; The'dfcontacts'in the kcall liifnder` OZ,"be1ongin'g ,to-incoming singlecurrent subscriberlines, are connected ytoA ground over "an individualcompensating A-resistance R3, shown in'Fig. 1. "In contra-distinctionthereto. the d-con-tact's belonging toinc'oiing doublecur- 'rentI'inesarenot-connected. A

If fthe d-Wiper encounters f ground, in case va single current`subscriber is' lcalling, "-rel'ay- EDRi operates' in a 'circuit 'frombattery, winding of relay EDRi, the back side of' itsinavke-oefore-break .contact", a make contact-ofrelayTKBR, call in'de'rWiper d `andthe locall c'ompens atingV resistance Rs to ground.Thereafter/relay"EDRijholdsitself" L'werfthe`r makeiside lof I its own`'make-bfcforebreakV contestan-d a` mairev c-dntac'tjofjrelay KBR. 'A'sthegmag'netiz'ation offrelay EDRliiSJDleClded,

'irfnie demper-cf the'canffinder does rnot undawayftoigrridfthe'operated'state'ofdiscriminat ingrelay EDR1" thus` forms'the criterion for" the connecting "cicuit, lhaving' :been vseiaedfrom"the callersside byasinglecurrent line. l

' By" theV n'ia'gnetiaationV of" relay; EDRgiffasgIecurientflineiislconnectedQ the v\ :s'1inding"s`orthe local 4lceivllgAruelar CVR 'i8rel iui/til're`d in as'sllOWiiih Fig. 3. Thel extremities*are connected',jrespec tively, to the `line, Iover the a-Wiper' of'call =finder OZ,"an`d`t0 ground foyer' the 'd-'Wipcifand,tiieindifyidu'al compensatinggresistanceRa. 'Thejunctofn of' the windings ofrelay GVB,l is 'jconnectefdf'to `{'po1c"of the bttciyi'the'eglstei,overajiiialie `contact 'ofr'elay EDR1,"c'utioi"cntactsf'i "relays DRiandKDR'ad ftheg-Wprfof theregister In consequence -ofthe"tract, that at"the opera# tion'o relay CORift-he' tonguev of ithe*right-'handccntactofthisrelay is-moved over `fro`m1-batteryin the exchange-tofveiebattery. inthe register, and .the leftl'ia'ndv tonguelf-'rom groundto telegraph battery, the' currentd-irection in theipolarized ArelayyER"-.is immerted-v sol that it.. elosesits contact. Rectiiiedvoltage is therefore suppliedto E land thereceiving magneteEof theteleprinter in seriesas termination oft-heone ,fpai-ifoffwires; the.other p'air'remainingunconnected; In the duplexposition .thetransmitting loop with-transe. Iinitting contacts; E and the 'receivingloop mth the-receivingmagnet F are separated, the:corre: spending pairso'f Wires respectively .terminating in thelocalreceiyi'ng relayOVRsandftheftngue of 'thev local transmitting :relay l.ZR ii-nfthewiex-l change. The transmitting loop may conta-inseln automatickeyer.

Fig'. 1 showsanexample of suchva-i subscriber installation. Ifl theduplex condition iis Wanted',

relay-DRse-is loperatedby'pushing :afkeyl D'Ii.. 'The subscriber seti'sconnected inlsimpiexlinecondi tion when relay DR?.vr isinnorma1positi.on-,.I:.and isl connected, 'in the duplex linecondition`when 'relay' DRa'is operated. .Y I

Relay DRa closesl `a hol-'ding "circuit A:for tscifb'yits lower makelcontact maintaining'th 'r'- cuitfafter'therelease of key-D151. On ftheopferati'on of the'duplexr relay DRS the rec'eiting magnet F -of theftelep'rinter vis -.switched.inria cir-'cuit`overthe b-'Wiper vofthecall finderOZfin i series with the-'relay DR1 i'n- 'the-'connectinglinkcA-14telegraph 1 battery, resistance Re, Winding DRr, make contacts "of"the -relays 'EDRi and AK13-R, blwip'er of call'iin'der OZ, upper makecontact-.Tof i'el'ayY DR-s, v receiving #magnet v"make si'de'lofxlefth'a'nd' changeoyer contact orela'y CDRi, Amtelegraph'b'attery. Asrelay-DB1operateajitclos'es side Vof vits makeebefore-breale"contact-andis 'in- Vse'rtcd inseries' between -l-batter'ylin the registerandtheiine connected Ito the-b-wiperof" the call finder OZ. 'Nou/'arepeatercircuitv is established aslshown in Fig. 4. Thefextreinities'othe-.Windingsrof relay CVR arecon'necte'dinthe same manner-las disclosedfor simplex'conditio'n. fI-IoW'ever-, fthe junction of the W'ndingsisconnectedf to tlalph battery' over a"i'nakefcontact 'of rela'yDRif.Bypushingkey DTz the subscriber'lnayiagain interrupt theoperating-'circuit for relay DR's. whereby this relayv andrela'y DRi-inthe connecting line.- arefreleased fand the connection 'of therclepeater toward the :caller becomes again-simp ex. o 1 i f Asthelcalling subscriber is nowfconnec'tedto theregister in a mannereasily to/besunderstodd fro'rnfFigs. 3 and 4, he' mayftransmitf theseriesof selecting impulses by means ofv thediaIl-"NSI, shown in Fig.`1,to'the receiving-'relay Oinf'the register.. `After the recording .orthefnumberl-b'y the register, the line to anotherexchange or--to anothersubscriber cn the same exchange lis! obtained, dependent on the recordednunriberiivr this' line :is found free. This selection; Whichlmaya-bedone in a` manner known from the Iusuallregister exchange systems, isshown-in principleLinlfFig.- 2 for thegroup-'selector GK. fFromthemoment Whenthe .contact 'gk is closedzbylvtheregisterthestartingrelay. SRs is operated in acircuit oyerlthe. -wiper ofthe:registerc'nder.` y.nRe'laySRa closes 7 ifslrrbntfcontat and thedriving' magnet of 'the group-selector GK is energized. Every step, madeby the group-selector GK, results in an evident manner in ade-energization of the relay UR in the register, the number of stepsbeing 'controlled by the register. When group-selector GK has made anumber of steps, which corresponds to the number, recorded in theregister, contact gk is opened and relay SRs and .driving vmagnet KMarelease their armatures.

'If the called subscriber is free, the corresponding cut-oir relay CORiwill be in normal condi- '.tion, and is operated in acircuit from-battery, the windingof .the corresponding relay CORi, a connecting wireto the corresponding contact in the row Cof the i'lnal selector, thec-wipers of the .group-selectors, the winding of relay KTR in theconnecting link, and a make contact of relay KBR to ground. Relay KTR isthus operated afterwhich the relays EDRz and DRz adapt the right handpart of the circuit to the kind of outgoing connection, in an analogousmanner as already described for the relays EDR1 and DRi.

If the called line is a single current line, relay EDRz is operated,jasground is supplied to the corresponding contact in the row dof the nalselector; owing to the operation of relay EDR2 a circuit is vestablishedfor relay DRz over the b-Wiper of the iinal selector, if wanted by thecalled subscriber. The circuits for local transmitting relay ZRestablished by these switchings are similar to those for local receivingrelay OVR and are shown in Figs. 3 and 4. The printer motor of thecalled subscriber is started by the inversion of the current directionin the subscriber loop as a result of the operation of correspondingrelay CORi. The register action may then be terminated by the switchingthrough relay KDR to which ground is applied at this moment by an actionof the register over wiper e of the register finder RZ. For simplex thejunctions of the windings of one local receiving relay OVR and one localtransmitting relay ZR are through-connected one to the tongue of theother. For duplex the tongues of these relays are connected to thereceiving coils of the subscribers. From this moment the identificationcombination of the called subscriber may be transmitted, so that thissubscriber may now transmit his name and number toward the caller as asignal, that the connection is established.

During the several actions described, circuits .are established for thetWo supervisory relays `CRi and CRQ.. By the action of relay EDRi thejunction of the windings of the local receiving relay OVR is connectedto -l-battery in thev regisiter over a make contact of relay EDRi and acutoi contact of relay DB1. (Fig. 3.) The currents in the left and righthand winding are now such, that; the tongue of relay OVR is moved overto side of telegraph battery, if it was not already against this side.Relay CR; is now energized in a circuit from -telegraphbattery,resistance R1, a make Contact of relay KBR, Winding of relay CRi,spacing side of the tongue of local receiving relay OVR to -i-telegraphbattery. Relay CRz operates likewise in a circuit from V telegraphbattery, resistance Rz, make contact of relay KBR, windings of relayCRB, cut-oli contact of relay KDR, g-wiper of register finder RZ to-i-battery in the register.

The function of the relays CR1 and CB2 is to establish a holding circuitfor the cord seizure relay KBR, which circuit may be interrupted bythese relays when Ydesired by the subscribers.

Relay CR: supervises thec'onnectionv toward the calling subscriber,relay CB2 supervises theconrie'ction toward the called subscriber. Thecaller, as Well as the called subscriber, are able to interrupttheconnection by pushing the release key'ST of Fig. l for some moments,e. g. 200 milliseconds. This key interrupts, when pushed down bythecalling subscribentheloop terminated by the local receiving relay CVR,and when pushed down by the called subscriber, the Vloop terminated bytheV local transmitting relay ZR. As a consequence'the tongues our, orar, respectively, ofthe relays OVR or ZR, move'over to .-battery for atime which is long enough v4to release theislowly actuated relays CRi orCRz. The breaking of the holding circuit of relay KBR. restores thelinkto free condition. Relays CRi and CRz must be slow releasing relays,since they are not to release, When during the spacing elements of therepeated telegraph signals the tongues of the relays OVR and ZR arebrought against battery If the connection is not yet fullycompleted, thecaller may stop the building up of the Aconnection by pushing therelease key ST, causing relay CRi to be released, Whereas the registervmay release the connection by demagnetizing relay CB2, if the calledsubscriber is found busy. The word busy may be transmitted to the callerby the register, before the release occurs. y

From the foregoing description of the adaptation of the repeater to asingle current jline and the building up of the connection betweensubscribers, it will bev clear that the repeater is in normal positionsuitable for the interconnection of double current lines, vas relaysEDRi, EDRz, DRi and DB2 are in non-operated position.

As described hereinbefore the contacts in the d-row ofthe call iindersOZ are not connected lto ground for double current-lines.v Thus, afterthe operation of the cord seizure vrelay KBB,vv no ground is applied tothe relayv EDR1, this relay remaining now notoperated. As the operatingcircuit for relay DRicontainsa. make contact of relay EDRi, ,relay DR1does' not operate either. Fig. 5 shows the repeater circuit, that isestablished in this case. The windings of the local reoeiving relay OVRare switched in series between the tongue of the trunk receiving relayITL. OVR and ground, over a cut-off contact of, relay EDRi. The junctionof the windings remains unconnected, owing to an open make contact ofrelay EDRi. The trunk transmitting relay ITLLZR is, over the b-Wiper andcut-oil contacts of'relays EDRi and DRi, connected to the tongue-ofrelay ZR when relay KDRV is energizedby the register. The called side ofthe repeater may be adapted to the kind ofthe called line in a waysimilar to that described for a single'currcntline, or toi-,hatdescribed now fora double current line. 1 Furthermore, a free registermaybe seized in ,the same manner as by a' local 'subscriber by adistrictsubscriber or Vby another exchange, the junction lines of` whichto the "exchange are double current lines. In normal condition thearmature of the trunkv receiving relay ITLQVR is against'jpoleofbattery. At an incoming subscribers call, which is characterized in-thejemission of voltage on the trunk line by the subscriber, the tongueis moved toward |v pole oi' battery, and line relay DRn is energized ina er4 cuit from -i-telegraph battery, over the tongue-of relay ITLDVR,the back Vcontact of the upper change-over contactofrelayCORz, and thewind-A ings of -relay LR21 to -'battery. .Theconsecutive switchings,resulting inthe seizure of a frescor;-

netting' .linkand a free register,follow vin the same manner as,`,described for a single `current subscriber.

.AS soon'as the ,relay KBR operates, ground vis applied to the left handwinding of relay CVR,

and the tongue of this relay moves over to the side of telegraphbattery, as marking current yis sent by the calling subscriber. Thus theoperating circuits for slow'ireleasing supervising relays CRi and CRzare established.

It is observed, that. subscribers connected to the'exchange over doublecurrent lines have also apossibility to work duplex with the arrangementof the invention. lThese subscribers are connected over a localv singlecurrent line to av re- Deater, .inverting the single current signals todouble current signals over the interlocal double current line to theexchange. The ytrunk ljunc-4 tion lines are suitable for duplex-trahie.The adaptation ofv the subscriber set to the four wire traic, whichv hasonly consequences on the single current part `of this connection to theexchange, has ncinuence on the condition of the trunk junction line andthe repeater in the connecting link .of the automatic exchange,

I claim: Y r

1. A telegraph system comprising in combination,a plurality of stationsincluding at least one station having a single current lineand at leastone station having a double currentline; `a repeater; .means forconnecting said-stations to said repeater one at a time; a receivingrelay in said repeater .receiving telegraph signals. emitted by .saidone: .oi .said stations connected `to said repeater, said receivingrelay having a iirst winding and asecond windingconnected in series toeach other; a discriminatory relay in said repeater; means forenergizingsaid discriminatory relay' when one .of said stations havingv asnglecurrent line is connected tosaid repeater, said discriminatory relayremaining de -energized when one of said stations having a doublecurrent line is connected to said repeater; a grounded resistor; airstcontact controlled by said dis-` criminatory relay and connected tothe junction of saidwindings of said receiving relay, said first contactbeing closed upon .energization ofv said discriminatory relay andconnecting the junction of said windingsto battery voltage; and a secondcontact controlled. by said discriminatory relay and connected to theend of said iirst wind# ing different from the junction of saidwindings,4 said second contact connectingsaid firstwinding' to saidgrounded resistor when said .discriminatory relay is energized, anddirectly to .ground when said discriminatory relay is rie-energized. n2. A telegraph system comprising in combina tion, a plurality ofstations Vincluding at least one station having a single current lineand at least one, station having a double current line; means'forchanging at leastone. of said stations having a single current line fromsimplex to duplex' Vand vice versa; a repeater; Ameans for connectingsaid ,stations to said 'repeater' one at a time; a receiving relay insaidr repeater receiving vtelegraph Vsignals emitted by said one of saidstations connected to said repeater, said receiving relay having a.first winding and a second winding connected inseries to each other; ars't discriminatory relay ,in said repeater; means for energizing saidfirst discriminatory relay when one of said stationshaving a singlecurrent line is connected `tosaid repeater.; ASaid firstidiscriminatoryA relay remaining de-energized when one of said stationshaving a double current line is connected to said repeater; a

10 second discriminatory relay in said repeater; means `for energizingsaid second ydiscriminatory relay whenone of said .stations havingasingle current line is connected to said repeaterand changed fromsimplex to duplex; a grounded resister; a rst contact controlled by saidfirst discriminatory relay and connected to theiuijic-` tion of saidwindings of said receiving relay; .a contact controlled-by said seconddiscriminatory relay and connected in series tosaidiirst con--Y tact ofrsaid first discriminatory relay, .said first'. contact being closed uponenergization ,of said nrst discriminatory relay and connecting thejunctionoi said -windings to said contatggf said secondydiscriminai'fory relay, said contact of said second discriminatory`relay having two positionsr inwhich the sameis connected with oneterminal Vand v the `other terminal.- :respiri-rY tively,Y KAofbattery;` and Va second .contact .cone trolled by said.- iirstvdiscriminatory relay. connected to the. .end of said iirst windingferent. from the junction of saidwindings.V Said second contactnconnecting said lrsty winding .to said grounded, resistor when saidrstdiscrimina-- tory relay isenergized,v and directly to ground whensaid first. discriminatory relay, is deenergized. 1

3. A telegraph system Vcomprising in combi'rm.-v tion, a cord finderswitch having a lfirst bank of contacts, a firstwiper cooperating.therewithE a second banker contacts, a second -wiper.cooper` atingtherewith, a third bank of contacts, and a third wiper cooperatingtherewith; aplurality. of stations including at least one'statipn.having a single rcurrent line andzatleastone station having. av doublecurrent line nme ans for converting said one station haring a. singlecurrent line. from'simplexV to` .duplex and 'vice versa; a plurality oftransmitting contacts .andareceiving magnet forming .part of said onestation having. a single. .current line, said lplu-` k rality oftransmitting contacts and said .rcQeiY- ing magnet being `connectedin.series` toleach other when said one station having. .al Single. currentline is operating in simplex; means for connecting one `terminal ofVsaid plurality` of transmitting contacts to a. contact of said firstcontact bankY of. said cord kfinder switch;` means forming partV of saidconverting. means A and removing the seriesconnection of said pluralityof. transmitting contacts. and said receiving mag--v net and connectingthejsame to a contact of said second contact bank of said cord finderswitch;

means for .connecting the lines of said station' having a double currentiine, respectivelyfto other contacts of. .said first and second contactbanksof vsaidcord vfinder switch; a receiving relay in said. .repeaterreceiving telegraph ,signals emitted by any of said stations connectedto said. repeater over said cord nder switch; said. receivingrelayhaving two windings connected in series to. each other, one of saidwind; ings of said receiving relayl being connectedto said first wiperof -said cord Afinder switch a first discriminatory relay in said`repeater; means for energizing said first discriminatory: relayfwh'enone or said. stations having'a single currentline is connected tosaidrepeater, vsaid rst discriminatory relay remaining dre-energizedVwhen one of said stations having a double current vline is. connected tosaid repeater;- a second discriminatoryy relay in saidrepeater;gmeansjgfor energizing said second discriminatory3 relay whenonev of saidstations `having a single currezitline is connectedY to saidrepeater and changed-:from simplex to duplex; a grounded resistor con-11VV nectedto a contact of said third contact bank of` said cord finderswitch. said contact of said third contact bank being brushed by saidthird wiper simultaneously with the brushing by said rst and secondwipers, respectively, of said contacts of said first and second contactbanks c onnected to the terminals of said station having `a singlecurrent line: a first contact controlled by said first discriminatoryrelay and connected to the junction of said windings of said receivingrelay; a contact controlled by said second discriminatory relayconnected in series to said iirst contact of said iirst discriminatoryrelay, said rst contact being closed upon energization oi' said iirstdiscriminatory relay and connecting the junction of said windings tosaid contact of `said second discriminatory relay, said Vcontact of saidsecond Vdiscriminatory relay having two positions in which the same isconnected with one terminal and the other terminal, respectively, ofbattery; and a second contact controlled by said first discriminatoryrelay and connected to the end of the other of said windings of saidreceiving relay, said second contact connecting said other winding tosaid third wiper of said cord finder switch when said firstdiscriminatory relay is energized and directly to ground when said iirstdiscriminatory relay is de-energized, whereby when a station having asimplex single current line is connected to said repeater said rstdiscriminatory relay is energized and said second discriminatory relayis de-energized and said other winding of said receiving relay isconnected to ground over said resistor, when a station havingl a duplexsingle current line is connected to said repeater both saiddiscriminatory relays are energized and said other winding of saidreceiving relay is connected to ground over said resistor, and when astation having a double current line is connected to said repeaterneither of said discriminatory relays is energized and said otherwinding of said receiving relay is directly connected to ground.

4. A telegraph system comprising in combination, a cord iinder switchhaving a iirst bank of contacts, a rst wiper cooperating therewith, asecond bank of contacts, a second wiper cooperating therewith, a thirdbank of contacts, and a third wiper cooperating therewith; a pluralityof stations including at least one station having a single current lineand at least one station having a double current line; means forconverting said one station having a single current line from simplex toduplex and vice versa; a plurality of transmitting contacts and aVreceiving magnet forming part of said one station having a singlecurrent line, said plurality of transmitting contacts and said receivingmagnet being connected in series to each other when said one stationhaving a single current line is operating in simplex; means forconnecting one terminal of said plurality of transmitting contacts to acontact of said iirst contact bank of said cord nnder switch; meansvforming part of said converting means and removing the seriesconnection of said plurality of transmitting contacts and said receivingmagnet and connecting the same to a contact of said second contact bankof said cord finder switch; means for connecting the lines of saidstation having a double current line, respectively, to other contacts ofsaid first and second contact banks of said cord under switch; areceiving relay in said repeater receiving telegraph signals emitted byany of said stations connected to said repeater over said cord nderswitch, said receiving relay having two windings connected in series toeach other, one of said windings of said receiving relay being connectedto said first wiper of said cord nder switch; a iirst discriminatoryrelay in said repeater; means for energizing said iirst discriminatoryrelay when one of said stations having a single current line isconnected to said repeater, said iirst discrimina-tory relay remainingde-energized when one of said stations having a double current line isconnected to said repeater; a second discriminatory relay in saidrepeater, said second discriminatory relay being connected in series toa contactV closed by the energizationof said iirst discriminatory relay;means for energizing said second discriminatory relay when one of saidstations having a single current line is connected to said repeater andchanged from simplex to duplex; a grounded resistor connected to acontact of said third contact bank of said cord nder switch, saidcontact of said 'third contact bank being brushed lby said third wipersimultaneously with the brushing by said iirst and second wipers,respectively, of said contacts of said first and second contact banksconnected to the terminals of said station having a single current line;a iirst contact controlled by said iirst discriminatory relay andconnected to the `iunction of said windings of said receiving relay; acontact controlled by said second discriminatory relay connected inseries to said first contact of said first discriminatory relay, saidiirst contact being closed upon energization of said irst discriminatoryrelay and connecting the junction of said windings to said contact ofsaid second discriminatory relay, said contact of said seconddiscriminatory relay having two positions in which the same is connectedwith one terminal and the other terminal, respectively, of battery; anda second contact controlled by said first discriminatory relay andconnected to the end of the other of said windings of said receivingrelay, said second contact connecting said other Winding to said thirdwiper of said cord iinder switch when said first discriminatory relay isenergized and directly to ground when said first discriminatory relay isde-energized, whereby when a station having a simplex single currentline is connected to said repeater said iirst discriminatory relay isenergized and said second discriminatory relay is de-energized and saidother winding of said receiving relay is connected to ground over saidresistor, when a station having a duplex single current line isconnected to said repeater both said discriminatory relays are energizedand said other winding of said receiving relay is connected to groundover said resistor, and when a station having a double current line isconnected to said repeater neither of said discriminatory relays isenergized and said other winding of said receiving relay is directlyconnected to ground.

ROELOF M. M. OBERMAN.

REFERENCES CITED FOREIGN PATENTS Number Country use@ 'l Great BritainJan. 14, 1941-

